Microelectromechanical system (MEMS) microphones are used by today's consumers. For example, these microphones may be used in a variety of different customer electronic devices such as cellular phones or personal computers.
The microphones typically include a MEMS die (with a diaphragm and a back plate). The MEMS die is disposed on a substrate and the substrate is covered by a lid. Sound enters through a hole in the lid or through a hole in the substrate. The sound energy moves the diaphragm. This creates a current which can be further processed by an application specific integrated circuit (ASIC). The processed signal can be made available to electronic devices within the consumer device for further processing.
The communication path between the ASIC and the external electronic devices is made via the base. More specifically, conductive paths are disposed within the base. The ASIC is coupled to these conductive paths on one side (facing the interior of the microphone) of the base, while other pads are disposed on the other side (facing the exterior of the microphone) of the base. The external electronic devices couple to these pads. Unfortunately, the amount of space on a substrate is limited by the size (foot print) of the microphone. Consequently, when many pads (or large pads) are used, little space is left for the port opening. As a result, small port openings may have to be used because of the need for large pads on the bottom of the substrate. Small port openings often result in sub-optimal microphone performance.
These limitations have resulted in some user dissatisfaction with previous approaches.
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